【作者】 骆华勋；

【导师】 刘西拉；

【作者基本信息】 上海交通大学 ， 固体力学， 2012， 博士

【摘要】 钢筋混凝土作为一种传统复合材料,已经使用了一百五十多年了。在各种灾害作用下,钢筋混凝土建筑结构的破坏大都由拉、压、弯、剪、扭的不同组合引起。近百年来,许多研究者提出了众多计算方法及破坏理论,但是,这些理论模型多是把拉、压、弯、剪、扭分开来描述的,少数是把它们部分的组合起来描述。能把拉、压、弯、剪、扭完全组合在一起的计算只是非常个别的,由于引入了变形协调条件,使计算过程比较繁琐,甚至无法取得解析解,需要借助计算机进行大量的迭代计算而缺乏直观性,很难被工程界接受。一个成熟的能够被工程界接受的理论应该是充分利用塑性力学、断裂力学和组合材料力学的研究成果,不仅理论上应该是统一的、而且形式上是简明的。因此,依照这个标准,钢筋混凝土破坏理论目前还未成熟,但是要想取得一点进展又是十分艰难的。本文对钢筋分布比较均匀混凝土构件在复合受力下的破坏机理进行了较为全面、详细的分析和比较,特别对钢筋分布比较均匀混凝土构件的破坏做了以下几个方面的研究:首先,本文参考了较为成熟的Nielsen模型,采用经典弹塑性理论中的von Mises准则来考虑钢筋的销栓作用,采用混凝土Willam-Warnke五参数破坏模型对原拉断的Mohr-Coulomb混凝土破坏模型进行修正,进一步完善了钢筋均匀分布混凝土构件在轴力、弯矩、剪力、扭矩共同作用下的破坏统一理论。在新模型的基础上建立了钢筋均匀分布的混凝土薄壁构件在复合受力情况下的承载力统一表达式。其次,根据钢筋均匀分布的混凝土薄壁构件的特点推导出箱形截面下的破坏统一模型,将新模型以及原Nielsen模型的计算结果与现有大量的箱形截面试验数据进行对比分析,得出新模型的优缺点。并且根据上述的比较结果,归纳出新的破坏统一模型在实际应用中的限制条件。再次,作为模型的进一步拓展,本论文又进行了下述工作:(1)根据箱形截面的成果推导出环形截面的破坏统一模型。(2)考虑了平面内多向配筋情况下钢筋混凝土等效均质板的破坏统一模型,其破坏屈服条件可通过双向配筋板求取。(3)通过理论推导对比分析了钢筋混凝土等效均质板在单轴应力加载与单轴应变加载两种情况下承载力的不同。总之,论文改进的钢筋均匀分布的混凝土构件在轴力、弯矩、剪力、扭矩共同作用下的破坏统一模型更为合理,而且具有较大的工程参考意义。更多还原

【Abstract】 As a traditional composite material, the reinforced concrete has been used in structures for over one hundred and fifty years. The failures of reinforced concrete structures are mainly caused by different combinations of tension, compression, bending, shear and torsion. During the last one hundred years, many researchers have put forward many computational methods and failure theories. But, most of these models separate the actions of tension, compression, bending, shear and torsion. Only several models can describe different combination actions to some extent. A few can describe the full combination actions, because the computation process is very complex or even can not obtain analytical solutions when the deformation compatibility conditions are introduced. It needs to use computers to carry on a lot of iterations, which is less of intuitiveness. A mature theory should fully use the research contributions from plastic mechanics, fracture mechanics, compound material mechanics and should be expressed in simple way, which means that a perfect theory should be unified and expressed with simplicity. So, it can be concluded that the theory of reinforced concrete has not been mature yet. It is also recognized that any a little contribution to make the theory of reinforced concrete more mature is very difficult. In the present dissertation, based on existing material failure criteria, the failure mechanism of evenly distributed reinforced concrete members under generalized loading combination is analyzed fully and specifically. The following aspects are studied especially for the failure of evenly distributed reinforced concrete members:Firstly, according to the existing popular Nielsen failure model, the dowel action of reinforcement is considered by means of von Mises criterion and the Willam and Warnke five-parameter failure model is also introduced to adjust the original concrete failure model, which is so-called Mohr-Coulomb with tension cut-off. The original unified failure models of evenly distributed reinforced concrete members under combined actions of compression, tension, bending, shear and torsion are further improved, and the unified expression of evenly distributed reinforced concrete thin-walled members is derived under the generalized loading condition.Secondly, according to the features of evenly distributed reinforced concrete thin-walled members, the unified failure model on the box section members is derived. Then, the theoretical analysis results of both new model and Nielsen model will be compared with a large amount of experimental results so as to obtain the advantages and disadvantages of the new unified failure model. According to the comparing results, the limitations on application will be defined for the new unified failure model.Thirdly, on the basis of the unified failure model on box section, more research works have been extended, such as: (1) the unified failure model on annular sections, (2) the failure model of equivalent flat slab reinforced in arbitrary direction with different reinforcements, which can be considered into orthogonal reinforcement case, (3) the comparison and analysis of carrying capacity between uniaxial stress condition and uniaxial strain condition is conducted, which shows an important difference.In conclusion, the new unified failure model of evenly distributed reinforced concrete members under combination of axial force, shearing force, bending moment and torsion is more reasonable and meaningful for the application of unified failure theories in reinforced concrete structures.更多还原